Research Interests

The main focus of research in our group is the total synthesis of natural products possessing biological activity or interesting structural features. Concurrent with our syntheses of natural products, we are developing new synthetic methods. In the course of methods development, we have embarked on a program that utilizes the enzymatic Baeyer-Villiger oxidation to prepare optically active intermediates for a number of our final targets. As a result of our efforts in this later area, our research interests have broadened to include the study of enzyme reaction mechanisms utilizing a combination of substrate specificity and computer-assisted protein modeling.

Enantioselective synthesis utilizing readily available starting materials from the chiral pool are currently under way for a number of natural products. For example, the clerodane diterpenes which are typified by ajugarin I(1) and bacchofertin (2) begin with L-malic acid. The route to these compounds features a combination of inter- and intramolecular cycloaddition reactions. The alkaloid aristotlene (3) also is being prepared via a sequence that employs cycloaddition technology on an intermediate easily prepared from L-glutamic acid. The terpene (+)-carvone is the starting point in an enantioselective synthesis of the sesquiterpene aldehyde-lactone (+)-upial (4).

The enzymatic Baeyer-Villiger oxidation, a reaction that is capable of discriminating between the two enantiotopic carbons alpha to a ketone, is being utilized in connection with the total syntheses of a number of interesting natural products. The 3-acyltetramic acid antibiotic, tirandamyccin (5), is being prepared from a mesomeric cyclohexanone using this technique. A symmetrical bicyclo[2.2.1]hept-2-ene-7-one is being utilized in the preparation of shikimic acid (6) and the common branching point in the shikimate pathway, chorismic acid (7).